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PostPosted: Tue Feb 04, 2014 6:46 pm 
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Location: Ottawa, ON, CA
Hey all,

Just picked up a couple of these turntables that were represented to me as NOS, which does seem plausible since they have their original boxes.

The problem is, they were very poorly stored in a basement for the past 35 years; so besides being covered in dust and various other debris, all the bearing lubricant has long since hardened and/or poured out.

As they sit, both tables suffer from a loud rumbling/grinding noise when the platters are spun without the idler engaged. There was clearly dried oil or grease in the bearing wells and on the platter spindles, which I cleaned, but I'm not sure what to replace it with.

It seems like oil would be too thin for this application, so I'm guessing grease is required, but I have no idea what type or weight to look for, or how much to use.

Any suggestions or guidance would be greatly appreciated!


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PostPosted: Tue Feb 04, 2014 8:53 pm 
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I just use synthetic oil. Tear down those units and clean them right up. Any moving parts I use a little bit of lithium grease. Check the idler bearing. Inspect the idler wheel for flat spots and if it looks good use some rubber renew on it. Clean the motors and check the wiring. I like the old McCurdy broadcast tables but how much does that platter weigh? Oh yeah I forgot inspect any springs.

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PostPosted: Tue Feb 04, 2014 11:05 pm 
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As someone who is in the bearing industry and can comment on the care and feeding of ball bearings I would recommend the following:
1) If bearings have rubber seals then remove them VERY carefully and set aside.
2) Place bearings in varsol (or similar) over night. Do not wash rubber seals in a solvent, the seals will swell.
3) Carefully work out old grease, use small soft brush and be carefull not to overly rotate the bearing as once lube is flushed out as you will be down to metal on metal contact. NOT a good thing for bearings.
4) Flush bearings with a de-greaser like good "old" Break Clean (not the newer one for front wheel drives) this removes any oily residue left by the solvent. Cover with a clean cloth and let dry.
5) Once bearings are dry you can move to re-lubricating them.
6) Lithium is OK but these are small bearings and Lithium soap with a mineral oil base tends to be somewhat heavy (LNGI#2 or #3) and is considered a "wheel bearing grease".
7) I would recommend Kluber NBU15 this is a light buttery synthetic grease (LNGI#1), it has a very good tack factor and a excellent service life. (and no, I have no affliation with Kluber). You wont need much and it's not cheap 25 gram tube should be more than enough. Get it from your local bearing & power transmission house i.e. Motion Industries, Wajax, Applied Industrial, B.D.I. etc.
8) If you want to get real technical about the fill rate you can take O.D. of the bearing in mm X width in mm X 0.005 = grams of grease to apply (DxBx0.005=G or D in inches x B in inches x 0.114=Ounces). DO NOT OVER FILL!!!! Over filling adds drag & fiction.
9) Once grease has been applied work bearing slowly by hand to distribut grease within the bearing.
10) Replace seals (if any), rotate to ensure seals are set properly.
11) Carefully re-install bearing(s)
12) Fire up your table and let it run for 10~15 min's., listen for any odd noises, vibration etc.
13) Put on the tunes and enjoy!
:wink:


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PostPosted: Wed Feb 05, 2014 4:45 am 
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Location: Toronto, ON, CA
I have a McCurdy idler wheel turntable but do not know if it is exactly like yours. After cleaning as you did all I did to lubricate it was put some bicycle grease Pedros (I am a cyclist so I have this stuff around) at the tip of the cylinder where the sharp pint is and a light coating of bicycle oil (Finish Line Teflon) on the surface of the cylinder and reinserted it. Mine spins smoothly and quietly.

It's a great turntable. I put a SME series III arm on mine. Good luck with them.

Harry


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PostPosted: Thu Feb 06, 2014 2:50 pm 
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Thank you all for your advice and input!

The Glass Prison wrote:
I just use synthetic oil. Tear down those units and clean them right up. Any moving parts I use a little bit of lithium grease. Check the idler bearing. Inspect the idler wheel for flat spots and if it looks good use some rubber renew on it. Clean the motors and check the wiring. I like the old McCurdy broadcast tables but how much does that platter weigh? Oh yeah I forgot inspect any springs.


Okay, one vote for synthetic oil! Because these are potentially NOS, my plan is to leave them essentially as-is, but to get them in basic running order for testing purposes. While I appreciate the wisdom and necessity of doing some maintenance before putting the turntables into regular service, my intent at this point is just to test them.

wizard454 wrote:
As someone who is in the bearing industry and can comment on the care and feeding of ball bearings I would recommend the following:
1) If bearings have rubber seals then remove them VERY carefully and set aside.
2) Place bearings in varsol (or similar) over night. Do not wash rubber seals in a solvent, the seals will swell.
3) Carefully work out old grease, use small soft brush and be carefull not to overly rotate the bearing as once lube is flushed out as you will be down to metal on metal contact. NOT a good thing for bearings.
4) Flush bearings with a de-greaser like good "old" Break Clean (not the newer one for front wheel drives) this removes any oily residue left by the solvent. Cover with a clean cloth and let dry.
5) Once bearings are dry you can move to re-lubricating them.
6) Lithium is OK but these are small bearings and Lithium soap with a mineral oil base tends to be somewhat heavy (LNGI#2 or #3) and is considered a "wheel bearing grease".
7) I would recommend Kluber NBU15 this is a light buttery synthetic grease (LNGI#1), it has a very good tack factor and a excellent service life. (and no, I have no affliation with Kluber). You wont need much and it's not cheap 25 gram tube should be more than enough. Get it from your local bearing & power transmission house i.e. Motion Industries, Wajax, Applied Industrial, B.D.I. etc.
8) If you want to get real technical about the fill rate you can take O.D. of the bearing in mm X width in mm X 0.005 = grams of grease to apply (DxBx0.005=G or D in inches x B in inches x 0.114=Ounces). DO NOT OVER FILL!!!! Over filling adds drag & fiction.
9) Once grease has been applied work bearing slowly by hand to distribut grease within the bearing.
10) Replace seals (if any), rotate to ensure seals are set properly.
11) Carefully re-install bearing(s)
12) Fire up your table and let it run for 10~15 min's., listen for any odd noises, vibration etc.
13) Put on the tunes and enjoy!
:wink:


One vote for grease, with an excellent explanation - much appreciated! However, for the reasons mentioned above, probably way more information than I'll realistically use, at least for now. I plan to run the tables for a few minutes each for testing purposes and nothing more at the moment; though if the McCurdys impress me enough I may have to refer back to these instructions again!

frankhertz wrote:
I have a McCurdy idler wheel turntable but do not know if it is exactly like yours. After cleaning as you did all I did to lubricate it was put some bicycle grease Pedros (I am a cyclist so I have this stuff around) at the tip of the cylinder where the sharp pint is and a light coating of bicycle oil (Finish Line Teflon) on the surface of the cylinder and reinserted it. Mine spins smoothly and quietly.

It's a great turntable. I put a SME series III arm on mine. Good luck with them.

Harry


...and one vote for both grease AND oil! As an avid cyclist myself, I'm familiar with the products you've described; I've got some chain oil that I can use, but I'll still have to pick up some grease if I go this route.

This is the problem I had trying to Google this information: I couldn't find information specific to the CH-12, and other idler-drive turntables seem to have very particular requirements for their spindle bearings, either oil or grease. And so far, the advice given here has pretty much reinforced everything I've read elsewhere in terms of general advice, but I'm still not certain exactly what product this particular turntable needs.

I tried putting a small amount of chain oil in the bottom of the bearing reservoir (probably less than 1cc, just enough to cover the bearing) to see if the grinding noise would stop, which it did not. For that reason I'm leaning more towards grease right now.

So to sum up, and based on my limited plans for these, am I right to think that grease is the way to go, or should I consider using more, possibly thicker, oil? Besides testing, of course my other priority is to cause no damage; so am I right to think that grease would offer more protection, or will it be okay to use oil for testing purposes?

Thank you all again for your help, it's much appreciated!


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PostPosted: Thu Feb 06, 2014 4:19 pm 
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Location: Pitt Meadows, BC, CA
Huuuuum, in my experience once you hear grinding or feel rough spots in the bearing the damage is already done. You may be lucky and there may still be some old hard grease in the bearing that's causing the problem (may be). Bike chain oil does not have much viscosity to it so yes trying a thicker oil might help. Maybe a few drops of hydrualic oil, this is often used in high speed, high precision spindle bearings, or try a few drops of a simple 30w motor oil (multi grade is fine if that's you have in the garage).
Good luck!


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PostPosted: Thu Feb 06, 2014 6:16 pm 
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Ch-12s came in a variety of flavours over the years; but if it's like my blue topped version, just use any light synthetic oil on the bronze sleeves and spindle and a dab of lithium grease on the captive ball and you'll be fine. I use 3 in 1 non-detergent motor oil for the Ashland.

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PostPosted: Sun Feb 16, 2014 4:23 pm 
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Location: Ottawa, ON, CA
Thanks again to all who've offered their input and suggestions! With your help I've determined that I have a different problem than I originally suspected.

After having completely disassembled, cleaned and reassembled the bearing, I've come to the conclusion that it's not responsible for the grinding sound. The platter/bearing assembly itself is very quiet (when removed from the base of the turntable); barely audible when spinning the platter with my ear right beside it.

However, once installed back onto the turntable base, the grinding came back, with no real change in the volume or character of the noise.

I thought the idler wheel and drive spindle were fine - they spin silently on their own. But when putting the platter back on and simultaneously spinning it, it was obvious that the noise didn't start until it came into contact with the idler wheel.

To be sure, I played the 'table without the platter installed, and manually held the idler wheel in place against the drive spindle. Wouldn't you know it, the same grinding sound, somewhat more muffled since it wasn't being amplified by the platter, was present when the idler was being driven.

So now I've got to figure out how to reduce or eliminate THAT noise. I felt the idler wheel as it spun, and although it looks and feels brand new, there are small imperfections in the drive edge. I'm not sure if I'll need to recondition or replace the idler's rubber or bearing(s), or whether the motor/drive shaft could also be contributing to the noise.

I plan to start with the idler components, but am at a loss as to where/how exactly to begin. Ideally I'd like to start with the simplest maintenance, and ramp up to repair/replacement as necessary.

As with my original problem, I've searched for the basic info and am a little overwhelmed with all the conflicting information I've found. Should I start with oiling the components, or reconditioning the rubber, or...? The Glass Prison gave me some relevant advice above, but I'm not sure what's involved in checking the idler bearing, or even how to access it.

As always, any tips or advice are greatly appreciated!


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PostPosted: Sun Feb 16, 2014 4:51 pm 
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There's not much to the idler bearing. If you haven't already, just pop off the c clip with a screwdriver. There should be a washer under it and another under the idler wheel. I replaced mine with teflon washers. If you have tremendous play on the wheel when it is on the post, you might want a knackered bronze bearing. Apart from cleaning and reoiling there's not much you can do tho, aside from replacement, but it shouldn't be grinding unless there is a protrusion on the post or bearing. All this assumes the wheel rubber is ok, but usually that causes a periodic thump rather than a grinding sound. You may find that you always get a little noise from the idler turning, trick then is to prevent it getting to the needle. When you say the platter is amplifing the noise - do you have a mat on? The platters ring like a bell without one.

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PostPosted: Sun Feb 16, 2014 5:04 pm 
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canzld wrote:
There's not much to the idler bearing. If you haven't already, just pop off the c clip with a screwdriver. There should be a washer under it and another under the idler wheel. I replaced mine with teflon washers. If you have tremendous play on the wheel when it is on the post, you might want a knackered bronze bearing. Apart from cleaning and reoiling there's not much you can do tho, aside from replacement, but it shouldn't be grinding unless there is a protrusion on the post or bearing. All this assumes the wheel rubber is ok, but usually that causes a periodic thump rather than a grinding sound. You may find that you always get a little noise from the idler turning, trick then is to prevent it getting to the needle. When you say the platter is amplifing the noise - do you have a mat on? The platters ring like a bell without one.


Hi canzid,

Thanks for your kind reply!

I haven't done anything yet, but I'll try what you've suggested and report back.

It's possible there's also a thump sound coming from the idler as well, but if so then it's being masked by the grinding sound, which is loud enough that you can easily hear it from across the room (and again, this is with the turntable disconnected from my amp, ie. the sound is purely mechanical in nature).

With the platter removed and holding the idler wheel against the drive shaft as I described above, the grinding noise is probably about 50% quieter than with the platter installed. With the platter on, it doesn't really matter if I use a mat or not, the grinding sound is plainly audible. This is definitely not a case where minimizing the rumble will be adequate - for comparison, it sounds like a grinding wheel being used to hone a piece of metal (okay maybe a little less loud, but the same kind of noise).


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PostPosted: Sun Feb 16, 2014 6:21 pm 
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Have you checked the motor bearings yet? That should be your next step after the idler bearing.


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PostPosted: Sun Feb 16, 2014 6:29 pm 
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OBI56 wrote:
Have you checked the motor bearings yet? That should be your next step after the idler bearing.


Hi OBI56,

Thanks for the suggestion, I'll try that next if my efforts on the idler bearing don't bear fruit!

Just wondering, is the motor bearing similar to the idler bearing, where any 'bad' noise will only be audible when it's loaded, or should I be able to hear it with just the motor running by itself (which I can't)?


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PostPosted: Sun Feb 16, 2014 6:47 pm 
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Too Much Stuff wrote:
which is loud enough that you can easily hear it from across the room


ok - that's pretty loud and sounds very un-idler bearing like. I'm assuming you oiled the motor? I have to say that it sounds like the stator could be hitting the windings (or something) when you load it sideways. Take a pencil with an eraser and using that end and gently lean on the rotor as it spins for a quick and dirty test. Although I find your progress so far a little confusing, if both of your tables are doing this, it probably is the motors.

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PostPosted: Sun Feb 16, 2014 7:59 pm 
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Too Much Stuff wrote:
OBI56 wrote:
Have you checked the motor bearings yet? That should be your next step after the idler bearing.


Hi OBI56,

Thanks for the suggestion, I'll try that next if my efforts on the idler bearing don't bear fruit!

Just wondering, is the motor bearing similar to the idler bearing, where any 'bad' noise will only be audible when it's loaded, or should I be able to hear it with just the motor running by itself (which I can't)?


Idler drives like belt drives put a signi9ficant side load on the mo0tor bearins. This is in sharp contrast to direct drives. Unloaded idler drive motors can be completely silent and remain relatively quiet up to their rated load but get really noisy past that point, sort of like car wheel bearings which can be dead quiet on the lift but noisy on the road with the car weight on them. Canzid's suggestion of using a pencil eraser is a very good one but so is using the lead end of a thick carpenter's pencil or a beeswax candle. With noise problems it pays to be systematic and to go from 1 end to the other in sequences without skipping any step in the transmission chain. Jumping around from place to place gets you nowhere fast unless you are lucky enough to hit the right spot by accident.


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